The present invention related to performance prediction methods for predicting in an early stage of development performance of an integrated circuit which is intended to be developed and methods for designing the integrated circuit.
In recent years, there have been increased level of fine, very large scale and high performance integrated circuits and systems including such integrated circuits. Performance prediction techniques are of a development process which is used across both of designing and manufacturing processes. For example, performance prediction techniques are used when a design engineer predicts circuit performance from a preliminary designing process specification in an early stage of development and also when a manufacturing process engineer predicts manufacturing process conditions to achieve required circuit performance. Purposes of performance prediction techniques are to seek an optimum combination of conditions for both of designing and manufacturing processes and to make it clear at an early stage whether required performance can be possibly achieved and then give a clear direction for development.
As a known performance prediction technique, there has been disclosed in Japanese Unexamined Patent Publication No. 10-284606 a performance prediction technique, in which a logic circuit is hierarchically represented by model equations, values are input into input variants of the model equations related to each other, calculations are performed, and then predicted values of circuit performance can be obtained. In the performance prediction technique, conditions for designing and manufacturing processes can be represented as parameters in a simple manner using model equations and also effects of the conditions on performance of the circuit can be evaluated. However, between integrated circuits of different process generations, it is difficult to associate model equations with each other. Thus, there is a limit to expression of the effects depending on each circuit. Moreover, if a model equation is built for each process generation, a very accurate model equation can be obtained but a large number of process steps are required.